JP2001097989A - Method for purifying metallocene compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and efficient method for isolating and purifying a racemic metallocene compound from a mixture of cross-linked metallocene reaction products each having a halogen-containing substituent. SOLUTION: The objective racemic metallocene compound is isolated and purified by dissolving or dispersing in a halogen-containing aromatic hydrocarbon solvent such as chlorobenzene or o-dichlorobenzene a reaction product mixture obtained in synthesizing cross-linked metallocene compounds each having a halogen-containing substituent and then by performing heat treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for isolating and purifying a racemic metallocene compound from a product mixture formed during the synthesis of a bridged metallocene compound having a halogen-containing substituent.

[0002]

2. Description of the Related Art Metallocene catalysts known as .alpha.-olefin polymerization catalysts are characterized by high polymerization activity and the ability to obtain polymers having a narrow molecular weight distribution. In particular, by using a stereorigid transition metal complex having a ligand having a structure in which two cyclopentadienyl groups are crosslinked,
It is known that isotactic polypropylene can be obtained (Journal of American Chemical Society 106).
p6355, 1984).

Furthermore, it is known that a polypropylene having high isotacticity can be obtained by a transition metal complex in which two cyclopentadienyl groups are cross-linked by a silicon atom (JP-A-63-295607). And JP-A-1-275609 and JP-A-2-131488. JP-A-6-239914 discloses that an α-olefin polymer having a higher melting point and a higher molecular weight can be obtained particularly when the cyclopentadiene derivative is an azulene derivative.

[0004] Such stereoregular polymerization of α-olefins is realized by a chiral metallocene compound. In particular, since racemic metallocene compounds exhibit higher stereoregularity than meso-form metallocene compounds, production of chiral metallocene compounds requires selective isolation and purification of racemic metallocene compounds. .

[0005] Generally, in the production of metallocene compounds, a considerable amount of organometallic by-products and / or inorganic by-products such as, for example, meso metallocene compounds are produced.
These by-products are mixed with the target metallocene compound in the product mixture in the metallocene compound synthesis,
If not removed, the catalyst performance will be significantly reduced in the olefin polymerization step.

[0006] As one method of purifying a metallocene compound,
A method of dissolving and removing the by-product by washing the product mixture containing the target metallocene compound with a solvent is also known. For example, JP-A-7-097388 discloses a metallocene compound which is obtained by washing a metallocene compound containing an ether compound as an impurity with a halogenated hydrocarbon solvent or a mixed solvent of a halogenated hydrocarbon and a hydrocarbon. Methods for purifying compounds are disclosed. However, in this method, the effect of removing organometallic by-products and / or inorganic by-products other than ether compounds is unclear.

Japanese Patent Application Laid-Open No. 9-176178 discloses a method for washing a metallocene mixture using a polar solvent such as alcohols and amines. However, the exemplified protic polar solvent may cause a problem in the stability of the metallocene compound. In particular, in the case of purifying a bridged metallocene compound having a halogen-containing substituent, since the solubility of the organometallic by-product is low, it may not be possible to sufficiently remove the by-product.

[0008] European Patent WO 97/21717 discloses a method for purifying a metallocene compound by subjecting a metallocene slurry to heat treatment in an aprotic polar solvent, followed by cooling to solid-liquid separation. In this method, tetrahydrofuran exemplified as an aprotic polar solvent generally easily forms an adduct with a metallocene compound, and its removal is not easy. Further, the metallocene compound to which tetrahydrofuran is added is unstable, and may cause a problem in storage. Furthermore, tetrahydrofuran tends to remain in the final product and is not easily removed. In addition, in the case of purifying a bridged metallocene compound having a halogen-containing substituent, since the solubility of organic by-products in the aprotic polar solvent used is extremely low, an extremely large amount of solvent is required to obtain a sufficient washing effect. The problem arises.

As another method of purifying a metallocene compound, there is a method of dissolving a target metallocene compound in an organic solvent to separate and remove by-products as poorly soluble components. For example, in JP-A-1-197490, a formed metallocene mixture is extracted with chloroform. JP-A-6-122592 and JP-A-6-26969
In JP-184179, the formed metallocene mixture is extracted with dichloromethane.

[0010] In such an extraction step, a large amount of extraction solvent is required in order not to decrease the recovery amount of the metallocene compound. In particular, in the case of a metallocene compound having a halogen-containing substituent, since the solubility in an aliphatic halogen-containing hydrocarbon as shown in the above example is low, the required amount of solvent becomes extremely large, which is a serious industrial production problem. It becomes a problem.

SUMMARY OF THE INVENTION The present invention provides a simple and efficient method for isolating and purifying a racemic metallocene compound of interest from a bridged metallocene product mixture having a halogen-containing substituent. As an issue.

[0011]

SUMMARY OF THE INVENTION We have disclosed a metallocene product mixture containing organometallic and / or inorganic by-products formed during the synthesis of bridged metallocene compounds having halogen-containing substituents. The inventors have found that the above-mentioned problems can be solved by treating with a halogen aromatic hydrocarbon solvent, and have completed the present invention.

That is, the present invention provides a method for isolating and purifying a racemic metallocene compound from a product mixture obtained in the synthesis of a bridged metallocene compound having a halogen-containing substituent, wherein the product mixture is a halogen-containing aromatic compound. Provided is a method for purifying a metallocene compound, which is characterized by treating with a hydrocarbon solvent.

Further, the present invention provides the above purification method, wherein the bridged metallocene compound is a bridged cyclopentadienyl compound represented by the following general formula (I).

[0014]

Embedded image

(In the general formula (I), R ¹ , R ² , R ⁴ , R
⁵ each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 18 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms. R ³ and R ⁶ each independently have 3 carbon atoms forming a condensed ring with respect to the 5-membered ring to which
And 10 to 10 saturated or unsaturated divalent hydrocarbon groups.
R ⁷ and R ⁸ are substituents for replacing a hydrogen atom on the condensed ring R ³ or R ⁶ , and are each independently a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms,
A halogenated hydrocarbon group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, or a sulfur-containing hydrocarbon group having 1 to 20 carbon atoms. However, at least one of R ¹ , R ² , R ⁴ , R ⁵ , R ⁷ and R ⁸ is a halogen atom or a carbon atom having 1 to 20 carbon atoms.
Is a halogenated hydrocarbon group. m and n each independently represent an integer of 0 to 20. When m or n is 2 or more, R ^{7 and} R ⁸ may be connected to each other to form a new ring structure. When there are two or more R ⁷ and R ⁸ , each of the plurality of R ⁷ and R ⁸ may be the same or different. Q
Is a divalent hydrocarbon group having 1 to 20 carbon atoms, a silylene group which may have a hydrocarbon group having 1 to 20 carbon atoms, an oligosilylene group, a germylene group Indicates either. X and Y are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, It represents an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, and M represents a transition metal of Group 4 to 6 of the periodic table. ) Is provided.

Further, the present invention provides a compound represented by the formula (I)³
And R⁶At least one of R ³Or R⁶Of origin
Forming a fused ring consisting of a 7-membered ring having an unsaturated bond
The purification method is provided. Also book
The invention is characterized in that the halogen-containing aromatic hydrocarbon solvent is chloro
The above purification method, wherein the purification method is benzene or o-dichlorobenzene.
Provide the law.

As described above, the present invention provides a method of dissolving or dispersing a crosslinked metallocene synthesis product mixture containing an organometallic by-product and / or an inorganic by-product in a halogen-containing aromatic hydrocarbon solvent and heating the mixture. And a method for isolating and purifying a racemic metallocene compound from the product mixture.

[0018]

Embodiments of the present invention will be described below. The method of the present invention is a method for isolating and purifying a racemic metallocene compound from a product mixture obtained by synthesizing a bridged metallocene compound having a halogen-containing substituent.

(1) Bridged Metallocene Compound Having a Halogen-Containing Substituent The crosslinked metallocene compound having a halogen-containing substituent to be subjected to the purification treatment in the present invention is a metallocene compound which is usually used as a catalyst component for α-olefin polymerization. Although not particularly limited, the following general formula (I) is preferable.
Is a crosslinked cyclopentadienyl compound represented by the formula:

[0020]

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R ¹ , R ² , R ⁴ , R ^{5 In the} general formula (I), R ¹ , R ² , R ⁴ , R ⁵ each independently represent a hydrogen atom, a halogen atom, a carbon number of 1 to 20. A silicon-containing hydrocarbon group having 1 to 18 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms.

Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Of these, a chlorine atom is preferred. 1 to 2 carbon atoms
Specific examples of the hydrocarbon group 0 include methyl, ethyl, n
-Propyl, i-propyl, n-butyl, i-butyl,
Examples include alkyl groups such as s-butyl and t-butyl, alkenyl groups such as vinyl and propenyl, arylalkyl groups such as benzyl and phenylethyl, and aryl groups such as phenyl, tolyl and 1-naphthyl.

Specific examples of the silicon-containing hydrocarbon group having 1 to 18 carbon atoms include trialkylsilyl groups such as trimethylsilyl, triethylsilyl and t-butyldimethylsilyl; triarylsilyl groups such as triphenylsilyl;
(Alkyl) (aryl) such as dimethylphenylsilyl
Examples include an alkylsilylalkyl group such as a silyl group and bis (trimethylsilyl) methyl.

In the halogenated hydrocarbon group having 1 to 20 carbon atoms, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The halogenated hydrocarbon group is a compound in which a halogen atom is substituted at an arbitrary position in the above-mentioned hydrocarbon group having 1 to 20 carbon atoms. That is, for example, when the halogen atom is a fluorine atom, a compound in which the fluorine atom is substituted at an arbitrary position of the above-mentioned hydrocarbon group having 1 to 20 carbon atoms, specifically,
Examples thereof include fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl, and iodomethyl groups.

R ⁷ and R ^{8 In the} general formula (I), R ⁷ and R ⁸ are substituents for replacing a hydrogen atom on the condensed ring R ³ or R ⁶ and each independently represents a halogen atom, C1-C20 hydrocarbon group, C1-C20 halogenated hydrocarbon group, C1-C1
-20 oxygen-containing hydrocarbon groups, amino groups, 1-2 carbon atoms
It represents a nitrogen-containing hydrocarbon group of 0 or a sulfur-containing hydrocarbon group having 1 to 20 carbon atoms.

Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Specific examples of the hydrocarbon group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n
Alkyl groups such as -butyl, i-butyl, s-butyl and t-butyl, alkenyl groups such as vinyl and propenyl, arylalkyl groups such as benzyl and phenylethyl, and aryl groups such as phenyl, tolyl, 1-naphthyl and biphenyl And the like.

In the above-mentioned halogenated hydrocarbon group having 1 to 20 carbon atoms, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The halogenated hydrocarbon group is a compound in which a halogen atom is substituted at an arbitrary position in the above-mentioned hydrocarbon group having 1 to 20 carbon atoms. That is, for example, when the halogen atom is a fluorine atom, a compound in which the fluorine atom is substituted at an arbitrary position of the above-mentioned hydrocarbon group having 1 to 20 carbon atoms, specifically, fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl , Dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl, iodomethyl groups and the like.

Specific examples of the oxygen-containing hydrocarbon group having 1 to 20 carbon atoms include methoxy, ethoxy, propoxy,
Examples include alkoxy groups such as butoxy, allyloxy groups such as phenoxy, methylphenoxy and naphthoxy, arylalkoxy groups such as phenylmethoxy and naphthylmethoxy, and oxygen-containing heterocyclic groups such as furyl groups.

Specific examples of the nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms include alkylamino groups such as methylamino, dimethylamino, ethylamino and diethylamino; arylamino groups such as phenylamino and diphenylamino; ) (Phenyl) amino and other (alkyl)
And nitrogen-containing heterocyclic groups such as (aryl) amino groups, pyrazolyl and indolyl.

Specific examples of the sulfur-containing hydrocarbon group having 1 to 20 carbon atoms include a substituent in which oxygen in the oxygen-containing compound is replaced by sulfur.

However, the above R ¹ , R ² , R ⁴ , R ⁵ , R
^At least one of ⁷ , ⁸ is a halogen atom or a halogenated hydrocarbon group having 1 to 20 carbon atoms.

R ³ , R ^{6 In the} general formula (I), R ³ and R ⁶ each independently represent a saturated or C 3-10 carbon atom forming a condensed ring with the 5-membered ring to which it is bonded. It represents an unsaturated divalent hydrocarbon group. Therefore, the condensed ring is a 5- to 12-membered ring. In particular, at least one of R ³ and R ⁶ , particularly preferably both, have an unsaturated bond derived from R ³ and R ⁶
Those forming a condensed ring composed of a membered ring are preferred.

Specific examples of the above R ³ and R ⁶ include:
Divalent saturated hydrocarbon groups such as trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, etc., propenylene, 2-butenylene, 1,3-butadienylene, 1-pentenylene, 2-pentenylene, 1,3
-Pentadienylene, 1,4-pentadienylene, 1-
Hexenylene, 2-hexenylene, 3-hexenylene,
Divalent unsaturated hydrocarbon groups such as 1,3-hexadienylene, 1,4-hexadienylene, 1,5-hexadienylene, 2,4-hexadienylene, 2,5-hexadienylene, and 1,3,5-hexadienylene are No.

In the general formula (I), m and n each independently represent an integer of 0 to 20. m and n are preferably 1 to 5. When m and / or n is an integer of 2 to 20, a plurality of groups R ⁷ and R ⁸ may be the same or different. When m or n is 2 or more, R ^{7 and} R ⁸ may be connected to each other to form a new ring structure.

Q In the general formula (I), Q has a divalent hydrocarbon group having 1 to 20 carbon atoms and a hydrocarbon group having 1 to 20 carbon atoms, which bond two 5-membered rings. Represents any of a silylene group, an oligosilylene group, and a germylene group. When two hydrocarbon groups or halogenated hydrocarbon groups are present on the silylene group, oligosilylene group or germylene group, they may be bonded to each other to form a ring structure.

Specific examples of the above Q include methylene,
Examples of alkylene groups such as 1,2-ethylene, arylalkylene groups such as (methyl) (phenyl) methylene and diphenylmethylene, alkylsilylene groups such as methylsilylene, dimethylsilylene and diethylsilylene, and methylphenylsilylene and methyltolylsilylene Alkyl) (aryl) silylene groups, arylsilylene groups such as diphenylsilylene, oligosilylene groups such as tetramethyldisilylene, germylene groups, and the above-mentioned silylene groups having a divalent hydrocarbon group having 1 to 20 carbon atoms. Examples thereof include an alkylgermylene group and an arylgermylene group substituted with germanium.

X, Y In the formula (I), X and Y each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a silicon-containing hydrocarbon group having 1 to 20 carbon atoms. , Having 1 to 20 carbon atoms
A halogenated hydrocarbon group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms.

Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The above-mentioned hydrocarbon group having 1 to 20 carbon atoms, 1 to 20 carbon atoms
Examples of the halogenated hydrocarbon group, the oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, and the nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms include the same groups as those described above for R ⁷ and R ⁸ . Can be

Examples of the silicon-containing hydrocarbon group having 1 to 20 carbon atoms include trialkylsilylmethyl groups such as trimethylsilylmethyl and triethylsilylmethyl, and dimethylphenylsilylmethyl, diethylphenylsilylmethyl and dimethyltolylsilylmethyl. Di (alkyl)
(Aryl) silylmethyl group and the like.

M In the general formula (I), M represents a transition metal belonging to Group 6 of the Periodic Table 4 and is preferably a transition metal belonging to Group 4 such as titanium, zirconium or hafnium, and more preferably zirconium or hafnium.

Specific Examples of Bridged Metallocene Compounds Examples of the bridged metallocene compounds to which the present invention is applied include the following compounds; dichloro [1,1′-dimethylmethylenebis {2-methyl-4- (4- Fluorophenyl) -4H-azulenyl}] zirconium, dichloro [1,1′-dimethylmethylenebis {2-methyl-4
-(4-chlorophenyl) -4H-azulenyl} zirconium, dichloro [1,1'-dimethylmethylenebis {2-methyl-4- (4-trifluoromethylphenyl) -4H-azulenyl} zirconium, dichloro
[1,1'-ethylenebis {2-methyl-4- (4-fluorophenyl) -4H-azulenyl]] zirconium, dichloro [1,1'-ethylenebis {2-methyl-
4- (4-chlorophenyl) -4H-azulenyl} zirconium, dichloro [1,1'-ethylenebis} 2-
Methyl-4- (4-trifluoromethylphenyl) -4
H-azulenyl}] zirconium, dichloro [1,1 ′
-Dimethylsilylenebis {2-methyl-4- (4-fluorophenyl) -4H-azulenyl} zirconium;
Dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3- Chlorophenyl)
-4H-azulenyl}] zirconium, dichloro [1,
1'-dimethylsilylenebis {2-methyl-4- (4-
Trifluoromethylphenyl) -4H-azulenyl}]
Zirconium-based metallocene compounds such as zirconium.

Further, dichloro [1,1′-dimethylmethylenebis {2-methyl-4- (4-fluorophenyl) -4H-azulenyl}] hafnium, dichloro
[1,1′-dimethylmethylenebis {2-methyl-4-
(4-chlorophenyl) -4H-azulenyl}] hafnium, dichloro [1,1′-dimethylmethylenebis} 2
-Methyl-4- (4-trifluoromethylphenyl)-
4H-azulenyl}] hafnium, dichloro [1,1 ′
-Ethylenebis {2-methyl-4- (4-fluorophenyl) -4H-azulenyl}] hafnium, dichloro
[1,1'-ethylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl]] hafnium, dichloro [1,1'-ethylenebis {2-methyl-4-
(4-trifluoromethylphenyl) -4H-azulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis} 2-methyl-4- (4-fluorophenyl)
-4H-azulenyl}] hafnium, dichloro [1,
1'-dimethylsilylenebis {2-methyl-4- (4-
Chlorophenyl) -4H-azulenyl}] hafnium,
Dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (3-chlorophenyl) -4H-azulenyl}] hafnium, dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4- Hafnium-based metallocene compounds such as trifluoromethylphenyl) -4H-azulenyl}] hafnium.

(2) Product Mixture The product mixture obtained in the synthesis of the bridged metallocene compound having a halogen-containing substituent in the present invention (synthesis of metallocene) is, in addition to the racemic metallocene compound to be isolated and purified, Contains organometallic and / or inorganic by-products. The metallocene product mixture is preferably a crude product formed directly during metallocene synthesis, but the crude product may be pretreated with any solvent, for example, toluene, hexane or the like.

Here, the term “organometallic by-product” refers to at least one carbon-containing ligand other than the intended racemic metallocene compound, particularly a π ligand, for example, a cyclopentadienyl ligand. Means all organometallic compounds bonded to a metal atom. Examples of "organometallic by-products" include metallocene compounds that are isomers of the desired racemic metallocene compound, other metallocene compounds that are not isomers of the target metallocene compound, and incomplete reactions in the synthesis of metallocene compounds. From the remaining organometallic compounds (eg, alkylmetal compounds), oligomeric and polymeric reaction products, and from the target racemic metallocene compound or any of the above by-products, impurities such as water, alcohols, amines, basic Compounds, compounds formed by reaction with air or by thermal decomposition, and the like.

The term "organometallic by-product" means
One or more components referred to above as "organometallic by-products" may be present in major amounts and the target metallocene compound may constitute only a small portion (eg, less than 50% by weight) of the mixture. Used.

The term "inorganic by-products" for the purposes of the present invention means, for example, inorganic salts, inorganic oxides or covalent metal halides (for example fluoride, chloride, bromide or iodide). Li as inorganic salts
F, LiCl, LiBr, LiI, NaF, NaCl,
NaBr, NaI, KF, KCl, KBr, KI, Ca
F ₂ , CaCl ₂ , CaBr ₂ , CaI ₂ , CsF, C
sCl, CsBr, CsI, MgF ₂ , MgCl ₂ , M
gBrCl, BaCl ₂ , BaI ₂ , AlF ₃ , AlC
l ₃ , AlBrCl ₂ , ZnCl ₂ , ZnBr ₂ , Cd
Cl ₂ and CdBrI are exemplified. Examples of the inorganic oxide include SiO ₂ , GeO ₂ , and SnO ₂ .
Covalent bond metal halides include Group 3 of the periodic table,
Group, Group 5 or Group 6, especially Group 4 metal halides, for example TiCl _4, ZrCl ₄ or HfCl ₄ is exemplified.

The term "inorganic by-product" means that one or more of the above-mentioned "inorganic by-products" are present in a major amount, and the target metallocene compound is a small part of the mixture (for example, 50 parts). (% By weight).

(3) Halogen-containing aromatic hydrocarbon solvent Examples of the halogen-containing aromatic hydrocarbon solvent used in the present invention include chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, o-chlorotoluene and p-chlorotoluene.
-Chlorotoluene, 1-chloronaphthalene, bromobenzene, o-dibromobenzene, 1-bromonaphthalene,
Examples include fluorobenzene and benzotrifluoride. Preferred halogen-containing hydrocarbons are chlorobenzene or o-dichlorobenzene.

In the present invention, one or more of these halogen-containing aromatic hydrocarbon solvents may be used in combination with another solvent. The order in which these solvents are added to the metallocene product mixture is not particularly limited.

Solvents that can be mixed and used include aliphatic hydrocarbons such as propane, butane, isobutane, pentane, and the like.
Aromatic hydrocarbons such as 2-methylbutane, neopentane, cyclopentane, hexane, 2-methylpentane, 3-methylpentane, heptane, 2-methylhexane, 3-methylhexane, cyclohexane, octane, isooctane, nonane, isononane, decane And benzene, toluene, xylene, mesitylene and the like.
The mixing ratio thereof can be set arbitrarily, but preferably the volume ratio of the halogen-containing aromatic hydrocarbon solvent to the other solvent is in the range of 100/0 to 1/99, more preferably 100/0 to 10/99. / 90 range.

(4) Treatment In the method of the present invention, the product mixture obtained in the synthesis of the bridged metallocene compound having a halogen-containing substituent is treated with a halogen-containing aromatic hydrocarbon solvent. More preferably, the product mixture is dissolved or dispersed in a halogen-containing aromatic hydrocarbon solvent and heat-treated.

That is, the treatment of the metallocene product mixture with the halogen-containing aromatic hydrocarbon solvent in the present invention is preferably such that the product mixture is dissolved in the halogen-containing aromatic hydrocarbon solvent, and the mixture is heated and stirred for an arbitrary time. It is to be. In this process, if there is an insoluble impurity component, it is separated by a known method using hot filtration using an arbitrary filter material. The liquid phase is then concentrated and allowed to cool to room temperature, or to room temperature without concentration,
Since the racemic metallocene compound is preferentially precipitated and the above-mentioned organometallic by-product and / or inorganic by-product can be dissolved in the liquid phase, the desired solid-liquid separation operation such as filtration and centrifugation is performed. Racemic metallocene compounds can be isolated and purified with high purity.

The treatment concentration of the product mixture in the present invention does not impair the recovery amount of the target racemic metallocene compound sufficiently, and after heating and cooling, removes the organometallic by-products other than the racemic metallocene compound to be removed. The concentration can be arbitrarily set as long as the concentration is such that inorganic by-products are sufficiently dissolved. It is preferably carried out in the range of 1 to 1000 g / L, more preferably 5 to 500 g / L, most preferably 5 to 200 g / L.

The treatment temperature in the present invention ranges from + 40 ° C. to reflux temperature, preferably from + 50 ° C. to reflux temperature. The time required for the treatment is not particularly limited, but is preferably 1 minute to 3 days, particularly preferably 5 minutes to 24 hours,
Particularly preferably, it is between 10 minutes and 6 hours.

In the present invention, the temperature at which the complex is precipitated after the heat treatment is not particularly limited. The maximum amount of the target racemic metallocene compound can be precipitated, and the maximum amount of organometallic by-products and / or inorganic by-products to be removed other than the target substance is kept in the liquid phase. Any temperature can be used as long as it can be set, and can be set arbitrarily.
Preferably -78 ° C to less than 40 ° C, more preferably -1.
It is carried out at a temperature of 0 ° C to 30 ° C, most preferably 0 ° C to room temperature.

The treatment with the halogen-containing aromatic hydrocarbon solvent in the present invention can be carried out several times. In other words, after the initial treatment, cooling to an appropriate temperature for an appropriate time and then heating to an optional temperature for an arbitrary time may be repeated an arbitrary number of times.

In the present invention, the solubility of the bridged metallocene compound having a halogen-containing substituent to be purified in a halogen-containing aromatic hydrocarbon is determined by the metallocene compound such as a halogen-containing aliphatic hydrocarbon or toluene / ether. It is considered that the reason why the effect of the present invention is exhibited is that the solvent is higher than that of a solvent commonly used for purification. That is, most of the complex can be uniformly dissolved due to high solubility, and it is easy to remove inorganic by-products and the like insoluble in the solvent,
Further, there is obtained such an advantage that the amount of a solvent used for purification can be reduced.

On the other hand, for example, when similar heat purification treatment is performed in a slurry state without dissolving the complex, there is a possibility that the removal of the solvent-insoluble components may be insufficient. In addition, when the solution is completely dissolved using a poorly soluble solvent and then precipitated by cooling, a problem arises in that a considerably large amount of solvent must be used. In the present invention, such a situation can be avoided and the purification operation can be performed, so that the merit in industrial production is great.

According to the method of the present invention, the metallocene compound can be easily purified and the quality can be improved with a good recovery rate.

[0060]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited by these examples unless departing from the gist thereof.

[0061]

Example 1 Into a 100 ml three-necked flask equipped with a reflux condenser and a thermometer, racemic / meso = 88.9 / 11.1.
(Molar ratio) of dimethylsilylenebis (2-methyl-4-
1.07 g of a metallocene product mixture containing 70.7% by weight of (p-chlorophenyl) dihydroazulenyl) zirconium dichloride and 29.3% by weight of impurities composed of inorganic salts and organic by-products was charged. 0.7 ml was added. Under nitrogen atmosphere, internal temperature 62
Shortly after heating and stirring at ℃, the reaction solution became a pale brown, almost transparent solution. After heating and stirring at the same temperature for 1 hour, the distillate quickly filtered while hot on a G4 frit was concentrated to a volume of about 40%, allowed to cool to room temperature, and then a yellow solid deposited on the G4 frit was collected by filtration. After washing with a very small amount of anhydrous chlorobenzene and anhydrous n-hexane, it was dried under reduced pressure to obtain 0.50 g of a yellow powdery solid. As a result of analysis by ¹ H-NMR, it was a pure complex of racemic / meso = 100/0 (recovery rate of racemic form: 80%).

[0062]

Example 2 In a 100 ml three-necked flask equipped with a reflux condenser and a thermometer, racemic / meso = 87.6 / 12.4.
(Molar ratio) of dimethylsilylenebis (2-methyl-4-
1.01 g of a metallocene product mixture containing 93.8% by weight of (p-chlorophenyl) dihydroazulenyl) zirconium dichloride and 6.2% by weight of impurities composed of inorganic salts and organic by-products was charged. .1 ml was added. Under nitrogen atmosphere, internal temperature 62 ℃
Shortly after heating with, the reaction solution became a pale brown, almost transparent solution. After heating and stirring at the same temperature for 1 hour, the distillate quickly filtered while hot on a G4 frit was concentrated to a volume of about 40%, allowed to cool to room temperature, and then a yellow solid deposited on the G4 frit was collected by filtration. An extremely small amount of anhydrous chlorobenzene and anhydrous n
After washing with -hexane and drying under reduced pressure, 0.74 g of a yellow powdery solid was obtained. As a result of analysis by ¹ H-NMR, it was a pure complex of racemic / meso = 100/0 (recovery of the racemate 89%).

[0063]

Comparative Example 1 Racemic / meso = 88.9 / 11.1 into a 100 ml three-necked flask equipped with a reflux condenser and a thermometer.
(Molar ratio) of dimethylsilylenebis (2-methyl-4-
1.07 g of a metallocene product mixture containing 70.7% by weight of (p-chlorophenyl) dihydroazulenyl) zirconium dichloride and 29.3% by weight of impurities composed of inorganic salts and organic by-products was charged. 0.7 ml was added. Under nitrogen atmosphere, internal temperature 40
The mixture was stirred with gentle reflux at ℃, but the complex was not completely dissolved and was a yellow slurry. After heating and stirring at the same temperature for 1 hour, the mixture was allowed to cool to room temperature, and the precipitated yellow solid was collected by filtration on a G4 frit. Negligible amounts of anhydrous dichloromethane and anhydrous n-
After washing with hexane and drying under reduced pressure, 0.69 g of a yellow powdery solid was obtained. As a result of analysis by ¹ H-NMR, the complex content in the solid was 83% by weight, racemic / meso = 87.1 /.
12.9 (molar ratio) (recovery of racemic form 79
%).

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Comparative Example 2 In a 100 ml three-necked flask equipped with a reflux condenser and a thermometer, racemic / meso = 88.9 / 11.1.
(Molar ratio) of dimethylsilylenebis (2-methyl-4-
1.07 g of a metallocene product mixture containing 70.7% by weight of (p-chlorophenyl) dihydroazulenyl) zirconium dichloride and 29.3% by weight of impurities composed of inorganic salts and organic by-products was charged. 0.7 ml was added. Under a nitrogen atmosphere, the mixture was heated and stirred at an internal temperature of 62 ° C., but the complex was not completely dissolved and was a yellow slurry. After heating and stirring at the same temperature for 1 hour, allow to cool to room temperature,
The precipitated yellow solid was collected on a G4 frit by filtration. After washing with a very small amount of anhydrous toluene and anhydrous n-hexane, dried under reduced pressure,
0.68 g of a yellow powdery solid was obtained. As a result of analysis by ¹ H-NMR, the complex content in the solid was 84% by weight, racemic / meso = 90.8 / 9.2 (molar ratio) (racemic recovery: 83%).

Table 1 summarizes the results of Examples 1-2 and Comparative Examples 1-2. In Table 1, “PhCl” represents chlorobenzene.

[0066]

[Table 1]

[0067]

According to the method for purifying a metallocene compound of the present invention, a racemic metallocene compound can be selectively isolated from a mixture of bridged metallocene products having a halogen-containing group easily and efficiently with a good recovery. It is a useful method that can be purified and quality can be improved.

Continued on the front page F term (reference) 4H050 AA02 AD10 AD15 BB12 WB11 WB12 WB13 WB14 WB17 WB21 4J028 AA01A AB00A AB01A AC01A AC10A AC28A AC39A AC41A AC42A AC44A EB03

Claims (4)

[Claims] 1. A method for isolating and refining a racemic metallocene compound from a product mixture obtained in the synthesis of a bridged metallocene compound having a halogen-containing substituent, wherein the product mixture is purified with a halogen-containing aromatic hydrocarbon solvent. A method for purifying a metallocene compound, which comprises treating. 2. The method according to claim 1, wherein the bridged metallocene compound is a bridged cyclopentadienyl compound represented by the following general formula (I). Embedded image (In the general formula (I), R ¹ , R ² , R ⁴ , and R ⁵ each independently represent a hydrogen atom, a halogen atom, a carbon number of 1 to 20.
A silicon-containing hydrocarbon group having 1 to 18 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms.
R ³ and R ⁶ each independently represent a saturated or unsaturated divalent hydrocarbon group having 3 to 10 carbon atoms which forms a condensed ring with the 5-membered ring to which R ³ and R ⁶ are bonded. R ⁷ and R
^{And 8} is a substituent for replacing a hydrogen atom on the condensed ring R ³ or R ⁶ , each independently being a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon having 1 to 20 carbon atoms. Group, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group, a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, or a sulfur-containing hydrocarbon group having 1 to 20 carbon atoms. However,
At least one of R ¹ , R ² , R ⁴ , R ⁵ , R ⁷ , and R ⁸ is a halogen atom or a halogenated hydrocarbon group having 1 to 20 carbon atoms. m and n are each independently 0
Represents an integer of up to 20. When m or n is 2 or more, R ^{7 and} R ⁸ may be connected to each other to form a new ring structure. When there are two or more R ⁷ and R ⁸ , each of the plurality of R ⁷ and R ⁸ may be the same or different. Q is two 5
A divalent hydrocarbon group having 1 to 20 carbon atoms,
Shows any of a silylene group, an oligosilylene group, and a germylene group which may have a hydrocarbon group having 1 to 20 carbon atoms. X and Y each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms,
A silicon-containing hydrocarbon group, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms, an amino group or a nitrogen-containing hydrocarbon group having 1 to 20 carbon atoms, and M is The transition metals of Group 6 from Periodic Table 4 are shown. The method according to claim 1, wherein 3. R of the general formula (I)³And R⁶Little
At least one is R ³Or R⁶With unsaturated bond of origin
A condensed ring consisting of a 7-membered ring
3. The method of claim 2, wherein 4. The halogen-containing aromatic hydrocarbon solvent,
The method according to any one of claims 1 to 3, wherein the method is chlorobenzene or o-dichlorobenzene.